LAPS/GFE Short Fuse Composite "Threat Area"(critical threshold values will be devloped in the future upon testing this spring)

Within the maximum of surface moisture convergence

Immediately downwind of the warm theta advection axis

Within the axis of highest surface based instability (CAPE and Theta-E)

Within the region of lowest surface based convective inhibition (0-2.5km AGL lapse rate)

Temporal and spatial continuity of at least 3 hours of all of the above

More information on the original Short Fuse Composite and its utility in nowcasting initiation and location of the most intense convective storms (that can lead to potential tornado development) can be found in this paper:

The charts are currently updating at :35 past the hour. (Future plans are to hopefully run LAPS earlier to get the valid time graphics updated perhaps as early as :20 past the hour.

The surface moisture flux convergence graphic is computed locally using MSAS hourly analysis wind fields (instead of LAPS). MSAS uses a better quality control algorithm to filter out poor wind observations, versus the LAPS analysis scheme. Testing has concluded that the moisture convergence field offered a better signal using MSAS winds in most convective events.

Warm Theta Advection, Theta-E, and CAPE graphics are all the internally calculated grids from within LAPS itself. (Future plans are to also calculate Theta Advection using MSAS winds, but the "potential temperature advection" grid from LAPS itself tends to have less noise than moisture convergence).

Latest Changes & Recent Events:

(6/20/2005) We have changed Chart 2 to remove surface-based CIN and use, instead, 0-2.5km AGL low level lapse rate. A discussion on this change can be found HERE